My next subwoofer project (1 Viewer)

[Patrick Sun]

Instead of doing yet another Sunosub project, I've decided to go with the wood box equivalent sub using the original SVS driver. I'm building this for a local friend/member.
We've settled on a 18"x18" footprint, looking at 4.5ft^3 to 5ft^3 of internal volume, tuned to 20Hz with a 16"-18" long flared 4" port. The internal height will be around 40", and width/depth will be 16.5"x16.5".
Driver will be down-firing, port though the top, a la SVS. Powered by the 250W plate amp on sale from MCM last week. Will have bottom plate as well, with 4"-6" legs separating the driver from the plate.
Bracing options are my main concerns. Should I just use horizontal layers (with holes cut into them to accomodate airflow and the port) and not much in terms of bracing in the vertical orientation? Or do I need some vertical bracing as well?
Links to other box sub constructions are welcomed, of course. TIA.

 

[Patrick Sun]

Judging by ThomasW's excellent writeup on the Link Removed, I may be able to get away with just horizontal braces, perhaps, every 10" apart.

 

[Brian Bunge]

Pat,
I would think that the horizontal braces would be the most effective. They will tie all four side walls together and really reduce panel resonances. The only other thing I can think of is maybe running a couple of braces across the top of the enclosure. I'd put them just to either side of the port and cut them so that they tie into the side walls. Maybe 16.5" long x 2" wide.
It could be a larger version of the ACI Titan II subwoofer enclosure pictured here. Scroll down to the bottom to download the PDF file for the full cabinet details.
Brian

 

[Patrick Sun]

Brian, excellent link! That's about what I envisioned when I was dreaming this up last night in my head, but with a port coming out on the top side. I think this is doable for roughly $300. Quite a deal if we can pull it off.

 

[Pete Mazz]

Pat building a box sub!!!
Sonotube manufacturers are going to have to lay off the night shift!
Pete

 

[Brian Bunge]

Pat,

Glad I could help! BTW, 4"-6" legs are truly overkill don't you think?

Brian

 

[Rudy H]

Pat check out Adire's box plans for the Shiva/Tempest, they have good bracing strategies there too.

 

[Patrick Sun]

Pete, I'm sure there's plenty on the HTF help take up the sonotube consumption slack.
Brian, I don't plan on flushmounting the driver, and the driver has this funky thick rubber cover that goes around the perimeter of the driver (think steering wheel cover), so that takes up almost an inch, so I think I'm in the right neighborhood if I go with 4" of clearance, if not more. My friend now has a SVS, so I'll ask him to measure the clearance on his SVS 20-39. Plus dowels are cheap.
Rudy, I'll give the Adire plans a looksie. Gracias.

 

[Kerry Hackney]

P@, you could also use an x brace pattern like in the Adire plans. That gives each panel support. If you are worried about panel flex just design in more supports.

If you use all horizontal layers you could run a few dowels from the top to bottom to support those faces. Glad to see you're coming over to the box camp. But, what are you gonna do with all those tubes????

Damn, you guys are just too fast...

 

[BryanZ]

Patrick,

I'd love to see the pictures/instructions of whatever you decide to do along with how it performs. I've got a driver and am seriously considering a design based upon either the Tempest or Titan II but have zero experience nor expertise in it.

 

[Patrick Sun]

Truth be told, the only reason I'm going with a box is because I didn't feel like messing around with mounting a plate amp on the side of a sonotube, plus I am using this exercise to see how a SVS driver behaves in a box (probably the same). I'm not even keeping this sub, it's going to Leo, who I knew was getting his dedicated HT room in shape after moving into a new house.
I thought about putting 2x2's along the vertical/horizontal seams inside the box between the bracing layers (I'll just route in circles or squares in the layers, but the 2x2's might be overkill when caulking would be sufficient if the bracing is in place).
The cats enjoy sleeping on Sunosub III.

 

[Trenton McNeil]

Patrick, just dropped in to say howdy. My sonosub still sounds amazing. I really appreciate your help from what, over a year ago?

Good to see you are still cranking out speakers! I bet you are becoming quite the adept woodworker!

 

[Patrick Sun]

Whoa, talking about coming out of the woodworks! Happy to see you're still cruising the HTF, Trenton! Glad to know that Tempest is still pounding away in the HT.

 

[GeorgeHolland]

Patrick,
You might consider small pieces of ¾” Baltic Birch glued to the sides and between the horizontal braces ala the North Creek Cabinet guide. The spacers are 2 ½” wide and as high as needed to fit between the braces. Use two per side for a extremely solid box.
Click on the first thumbnail from the following link for a cut away view.
http://photos.yahoo.com/bc/georgehol...Photos&.view=t
George

 

[ArmenK]

Pat, what do you plan on doing, if anything, to keep stuff from falling into the port, since its mounted on top?

 

[Chad Isaacs]

Just curious,do you use all of the subs together?

 

[Ben Ven]

Pat,
How thick are your panels going to be? I read an article in Audioxpress regarding various box building techniques. The author, I can't recall his name and I threw out that month's publication, went on to test different panel bracing and damping techniques. He measured the panel resonances and created some real nice cumalative delay plots (waterfalls) of the subject panels. Anyway, what he found was that there was no substitute for sheer brute force. 1.5" thick walls without bracing were the winners. That is how I built the box for my Shiva. One layer of 3/4" particle board and 3/4" MDF glued and screwed to the particle board. Can you say hernia!

 

[Patrick Sun]

George, pretty awesome box construction!
Armen, I'll probably use some sort of grill to cover the port to prevent stuff from falling into it.
Chad, I need my house to last, so, no, I don't run all my subs at the same time.
Ben, I ran the numbers, and if I want to keep the same footprint of 18"x18", I'll need to increase my internal height from 33" to 40" if I were to double up the walls and forego the bracing. So, you've given me food for thought. I'll ask Leo if he wants a heavier taller sub, or a shorter, lighter sub with less bracing.

 

[Brian Bunge]

Pat,

There won't be anything light about that sub! My dad's original sub was identical in construction to the link I posted above. We are now rebuilding it about 4" shorter and a few inches wider (same internal volume) to make it more like an end table.

My 1803 enclosure will be very similar to George's Leviathon enclosure except I'm looking at 1.5" walls with the same type of oak bracing that ThomasW used on his little Rava Too! sub.

Brian

 

[rodneyH]

Interesting that the Aerial sub was brought up, I was looking at a close pic of its internals and realized that they use the same/similar sub that SVS uses on the origionals with a different magnet (I bet it is slightly different, but the aluminum basket and driver look hte exact same), I was thinking htat it was a very cool design (I happen to have a spare SVS driver siting around, hmmmmm?)

btw, the aerial is a very expensive piece, ThomasW did an excellent job on his to replicate a beautiful unit.